Novel transparent polyurethane polyureas for lamination of glazing materials

ABSTRACT

The present disclosure is concerned with a novel transparent polyurethane polyurea which is particularly suitable for lamination to glass and glasslike transparent plastics. The polymer is the reaction product of high molecular weight diols, optionally low molecular weight diols, dihydroxy carboxylic acids, diisocyanates with only aliphatically and cycloaliphatically bound isocyanates and organic diamines having aliphatically and cycloaliphatically bound primary amino groups. It has specified contents of carboxyl groups and urea groups, and it has a minimum shear modulus at both 20 and 60° C. 
     The present disclosure is also concerned with a process for synthesizing such polymers. A preferred method is to react the diisocyanate and hydroxyl bearing compounds to prepare an isocyanate terminated prepolymer and chain extend with the diamine. 
     Also discussed are the production of film from these polymers by extrusion and solution casting, the production of laminates with glass and glasslike plastics and the laminates so produced. The solution cast or extruded films can be laminated to these substrates by the application of heat and pressure.

FIELD OF THE INVENTION

This invention relates to new polyurethane polyureas, to a process fortheir production and to their use in the production of glass-clearlaminates, especially laminated safety glass.

BACKGROUND OF THE INVENTION

Laminated safety glass is widely used in motor vehicle windscreens, asbullet-proof glass, for example for protecting bank and post officecounters, and as window glass, for example for reducing the danger ofinjury in the event of breakage and also, for example, as a safeguardagainst burglary and theft.

The interlayers used in these laminated glasses have to satisfynumerous, very stringent requirements. The following properties, inparticular, are of considerable importance, especially for the use oflaminated glass in motor vehicles:

1. A high energy-absorbing capacity in the event of sudden stressing asencountered on impact with blunt, but also sharp-edged bodies.

2. Adequate glass adhesion which is intended to prevent the glass fromshattering to any significant extent and causing injuries in the form ofcuts in the event of accidents.

3. High translucency; no hazing or clouding should occur.

4. A high degree of light stability, in other words the windscreensshould not turn yellow, even after prolonged exposure to sunlight.

5. High edge stability so that, when stored before fitting, thewindscreens should not undergo any delamination from the edges throughthe absorption of water.

These properties in general and those mentioned under (1) and (2) inparticular should be retained over as wide as possible a temperaturerange in which these materials are used.

In modified form, these requirements also apply to the use of theinterlayers in armoured glass and in safety glass of the type used inbuilding construction. Armoured glass is above all required to be bulletproof to a large extent. This makes it necessary to use an extremelytough interlayer.

Polyurethane interlayers for laminated safety glass are already known.Thus, according to German Offenlegungsschrift No. 2,302,400(corresponding to U.S. Pat. Nos. 3,823,060 and 3,900,446), polyurethaneinterlayers for laminated safety glass are produced from4,4'-methylene-bis-(cyclohexylisocyanate), a polyester containingterminal hydroxyl groups and having a melting point above 42° C. and amolecular weight of from 500 to 4,000, being the condensation product ofa dicarboxylic acid and a diol compound, and a chain extender which isan aliphatic or alicyclic diol containing from 2 to 16 carbon atoms.

Unfortunately, conventional polyurethanes have the serious disadvantageof poor adhesion to glass. However, glass-plastics laminates areintended to be of a structure such that no splinters of glass can bereleased from the plastics interlayer of the laminated glass in theevent of a collision. This requirement is not satisfied by conventionalpolyurethanes (cf. Example 7).

Accordingly, the object of the present invention is to obviate theabove-mentioned serious disadvantage of conventional polyurethanes and,in addition, to provide polyurethane polyaddition products of the typewhich, in addition to excellent adhesion to glass, show outstandingimpact strength over a wide temperature range, are free from hazing andlocal swellings, do not discolor on exposure to sunlight and showexcellent edge stability with respect to penetrating water.

This object is achieved by the polyurethane polyureas provided by theinvention.

SUMMARY OF THE INVENTION

Accordingly, the present invention relates to new polyurethane polyureashaving a predominantly linear molecular structure and exclusivelycontaining aliphatically or cycloaliphatically bound urethane and ureasegments with a shear modulus G' (DIN 53445) which amounts to between 2and 140 N/mm² at 20° C. and which does not fall below 1 N/mm² at 60° C.,characterized by

(a) a content of urea groups --NH--CO--NH-- amounting to between about 1and 20% by weight and

(b) a content of lateral carboxyl groups --COOH directly attached to themain chain of the molecule amounting to between about 0.001 and 10% byweight.

The invention also relates to a process for producing these polyurethanepolyureas by reacting on excess quantity of an organic diisocyanatecontaining aliphatically and/or cycloaliphatically bound isocyanategroups with a dihydroxy polyester and/or dihydroxy polyether having amolecular weight in the range from about 300 to 6,000, an aliphaticdihydroxy monocarboxylic acid and, optionally, an aliphatic orcycloaliphatic dihydric alcohol having a molecular weight in the rangefrom about 62 to 300, to form the corresponding isocyanate prepolymercontaining two terminal isocyanate groups, followed by reaction of thisisocyanate prepolymer with an organic diamine containing aliphaticallyand/or cycloaliphatically bound primary amino groups and having amolecular weight in the range from about 60 to 3,000, monofunctionalsynthesis components optionally being used in small quantities foradjusting the particular molecular weight required, wherein

(a) the dihydroxy carboxylic acid used corresponds to the formula##STR1## in which R represents hydrogen or an alkyl radical with 1 to 4carbon atoms, the quantity in which this dihydroxy carboxylic acid isused being such that the polyurethane polyurea obtained contains from0.001 to 10% by weight of lateral carboxyl groups, and

(b) the quantitative ratios between diisocyanates, dihydroxyl compoundsand diamines are selected so that the polyurethane polyurea containsfrom 1 to 20% by weight of urea groups --NH--CO--NH--.

Finally, the invention also relates to a process for producinglaminates, wherein sheets of silicate glass and/or transparent plasticsare coated and/or bonded together with the new polyurethane polyureas.

DETAILED DESCRIPTION OF THE INVENTION

The new polyurethane polyureas are non-yellowing, translucent clearthermoplasts with excellent edge stability and impact strength. Becauseof the presence in them of from about 1 to 20% by weight, preferablyfrom about 2 to 10% by weight, of urea groups --NH--CO--NH--incorporated in the chain, and of from about 0.001 to 10% by weight,preferably from about 0.008 to 6% by weight, of lateral carboxyl groups--COOH directly attached to the chain of the macromolecule, the newpolyurethane polyureas show excellent adhesion to glass and/ortransparent glass-like plastics, such as for example polymethylmethacrylate, polycarbonate or cellulose esters, and are thereforeeminently suitable for the production of laminated safety glass, theexpression "laminated safety glass" as used in the context of theinvention applying both to sheets of silicate glass or glass-likeplastics coated on one or both sides with the polyurethane polyureasaccording to the invention, and also to composite materials whichconsist of at least two sheets of silicate glass and/or glass-likeplastics bonded together with the polyurethane polyureas according tothe invention and which may additionally be coated on one or bothsurfaces with the polyurethane polyureas according to the invention.

Production of the polyurethane polyureas according to the invention bythe process according to the invention is preferably carried out on theprepolymer principle, i.e. by reacting an excess quantity of a suitablediisocyanate with dihydroxyl compounds to form the correspondingprepolymers containing terminal isocyanate groups, and subsequentlychain-extending these prepolymers with diamine chain extenders.Monofunctional reactants may optionally be used in small quantities inorder to regulate molecular weight and, hence, to adjust the physicalproperties of the polymer. In general, the type of synthesis componentsused and the quantitative ratios in which they are used are selected insuch a way as to give a theoretical molecular weight of from about10,000 to ∞, preferably from about 20,000 to 200,000. The difunctionalsynthesis components are generally used in such quantities in theproduction of the polyurethane polyureas according to the invention thatfrom about 1.1 to 4 and preferably from about 1.2 to 3 isocyanate groupsand from about 0.1 to 3, preferably from about 0.2 to 2, amino groups ofthe chain extender are used per hydroxyl group of the alcoholicsynthesis component.

Diisocyanates suitable for use in the production of the polyurethanepolyureas according to the invention are, in particular, diisocyanatescontaining aliphatically and/or cycloaliphatically bound isocyanategroups corresponding to the formula Q(NCO)₂, in which Q represents analiphatic hydrocarbon radical with 2 to 12 carbon atoms or acycloaliphatic or mixed aliphatic-cycloaliphatic hydrocarbon radicalwith 4 to 15 carbon atoms. Examples of diisocyanates such as these areethylene diisocyanate, tetramethylene diisocyanate, hexamethylenediisocyanate, dodecamethylene diisocyanate,cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate or1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane and mixturesof these diisocyanates. Cycloaliphatic or mixed aliphatic-cycloaliphaticdiisocyanates are preferably used in the process according to theinvention. 1-Isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane(isophorone diisocyanate) is particularly preferred.

The alcoholic synthesis components are

(a) the relatively high molecular weight diols known per se frompolyurethane chemistry having molecular weights in the range from about300 to 6,000, preferably from about 800 to 3,000,

(b) dihydroxy carboxylic acids corresponding to the formula ##STR2## inwhich R represents hydrogen or an alkyl radical with 1 to 4 carbon atomsand, optionally,

(c) low molecular weight aliphatic or cycloaliphatic diols preferablyhaving molecular weights in the range from about 62 to 300.

The quantitative ratios between the individual components (a), (b) and(c) which may be simultaneously or successively reacted with theisocyanate component, are preferably selected so that, for everyhydroxyl group of component (a), there are from 0.01 to 12 hydroxylgroups of component (b) and from 0 to 10 hydroxyl groups of component(c).

Component (a) may be any of the polyester, polyether, polythioether,polyacetal or polyester amide diols known per se. The polyester orpolyether diols known per se in polyurethane chemistry are preferablyused.

The polyesters containing hydroxyl groups suitable for use in accordancewith the invention are, for example, the reaction products of dihydricalcohols with dibasic carboxylic acids. Instead of using the freedicarboxylic acids, it is also possible to use the corresponding acidanhydrides or corresponding dicarboxylic acid esters with lower alcoholsor mixtures thereof for producing the polyesters. The dicarboxylic acidsmay be aliphatic, cycloaliphatic and/or aromatic and may be substituted,for example by halogen atoms, and/or unsaturated. Examples ofdicarboxylic acids such as these are succinic acid, adipic acid, subericacid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid,phthalic acid anhydride, tetrahydrophthalic acid anhydride,hexahydrophthalic acid anhydride, tetrachlorophthalic acid anhydride,endomethylene tetrahydrophthalic acid anhydride, glutaric acidanhydride, maleic acid, maleic acid anhydride, fumaric acid,terephthalic acid dimethyl ester and terephthalic acid-bis-glycol ester.Suitable dihydric alcohols are, for example, ethylene glycol, 1,2- and1,3-propylene glycol, 1,4- and 2,3-butylene glycol, 1,6-hexane diol,1,8-octane diol, neopentyl glycol, cyclohexane dimethanol(1,4-bis-hydroxymethyl cyclohexane), 2-methyl-1,3-propane diol,3-methyl-1,5-pentane diol, also diethylene glycol, triethylene glycol,tetraethylene glycol, polyethylene glycols, dipropylene glycol,polypropylene glycols, dibutylene glycol and polybutylene glycols.Polyesters of lactones, for example ε-caprolactone or hydroxy carboxylicacid, for example ω-hydroxy caproic acid, may also be used.

Particularly suitable dihydroxy polyesters are also the dihydroxypolycarbonates known per se which may be obtained, for example, byreacting diols, such as 1,3-propane diol, 1,4-butane diol and/or1,6-hexane diol, 3-methyl-1,5-pentane diol, diethylene glycol,triethylene glycol, tetraethylene glycol, with diaryl carbonates, forexample diphenyl carbonate or phosgene.

Suitable dihydroxy polyethers are also those known per se and areobtained, for example, by polymerizing epoxides, such as ethylene oxide,propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide orepichlorohydrin, on their own, for example in the presence of borontrifluoride, or by adding these epoxides, either in admixture orsuccessively, with starter components containing reactive hydrogenatoms, such as alcohols or amines, for example water, ethylene glycol,1,3- or 1,2-propylene glycol, 4,4'-dihydroxy diphenyl propane, aniline.In many cases, it is preferred to use polyethers predominantlycontaining primary hydroxyl groups, in particular up to 90% by weight,based on all the hydroxyl groups present in the polyether.

Component (b) is a dihydroxy carboxylic acid corresponding to the aboveformula, such as for example dimethylol acetic acid, α,α-dimethylolpropionic acid or α,α-dimethylol-n-valeric acid. It is preferred to useα,α-dimethylol propionic acid.

Component (c) is a glycol of the type already mentioned by way ofexample in the description of the polyesters.

Suitable diamine chain extenders are aliphatic, cycloaliphatic or mixedaliphatic-cycloaliphatic diamines preferably containing primary aminogroups and having molecular weights in the range from about 60 to 300.

Examples are ethylene diamine, tetramethylene diamine, hexamethylenediamine, 4,4'-diaminodicyclohexyl methane, 1,4-diaminocyclohexane,4,4'-diamino-3,3'-dimethyl dicyclohexyl methane or1-amino-3,3,5-trimethyl-5-aminomethyl cyclohexane (isophorone diamine).It is particularly preferred to use 4,4'-diaminodicyclohexyl methane orthe last of the abovementioned diamines, isophorone diamine.

As already mentioned, the theoretical molecular weight of thepolyurethane polyureas according to the invention should amount tobetween about 10,000 and ∞ and preferably to between about 20,000 and200,000. This resuls may be achieved both by using a small excess ofdifunctional isocyanate-reactive chain extenders or even by using smallquantities of monofunctional reactants. These monofunctional reactantsare generally used in quantities of up to about 3% by weight andpreferably in quantities of from 0.1 to 1% by weight, based on the totalquantity of the synthesis components. The following are mentioned asexamples of monofunctional reactants: monoisocyanates, such as methylisocyanate, cyclohexyl isocyanate, phenyl isocyanate; mono alcohols,such as methanol, ethanol, butanol, tert.-butanol, octanol, isopropanol,cyclohexanol; monoamines, such as methylamine, butylamine, dibutylamine.

In the case of the isocyanates and alcohols, the monofunctionalsynthesis components may actually be used during the production of theisocyanate-prepolymers while, in the case of the amines, they may beused during the chain-extending reaction. A possible variant forcontrolling molecular weight by using monofunctional synthesiscomponents is, for example, to react isocyanate-prepolymers producedfrom difunctional synthesis components with a small deficit of diaminechain extenders in the presence of monohydric alcohols, such asisopropanol for example, the isocyanate groups initially reacting withthe more reactive diamine until it has completely disappeared, afterwhich the residual isocyanate groups are subjected to achain-terminating reaction with the isopropanol used as solvent.

In the production of the polyurethane-polyureas according to theinvention, the isocyanate-prepolymers are generally produced at areaction temperature of from about 80° to 150° C. The end point of thereaction is determined by isocyanate group titration. Formation of theprepolymers is followed by the chain-extending reaction with the diaminechain extender either in the melt or even in solution.

Suitable solvents are, for example, methylene chloride, methanol orisopropanol. The chain-extending reaction may also be carried out withparticular advantage in heated reaction screw extruders. In general, atemperature of from about 120° C. to 300° C., preferably from about 150°C. to 250° C., is maintained during the chain-extending reaction.Preferably the polyurethane-polyureas are prepared in a twin-screwextruder according to the process disclosed in U.S. Pat. No. 3,963,679.

In addition, the type of synthesis components used and the quantitativeratios in which they are used are selected within the ranges quotedabove in such a way that the urea content and the content of lateralcarboxyl groups in the polyurethane polyureas correspond to the valuesquoted above, and in such a way that the shear modulus G', as determinedin the oscillating torsion test according to DIN 53445, amounts tobetween about 2 and 140 N/mm² at 20° C. and does not fall below a valueof about 1 N/mm² at 60° C.

For example, the joint use of cycloaliphatic or branched aliphaticsynthesis components, for example neopentyl glycol, as component c)produces an increase in the shear modulus.

In general, the polyurethane-polyureas according to the invention complywith the above-mentioned conditions regarding the shear modulus G'simply because of their content of urea groups --NH--CO--NH-- essentialto the invention, because any increase in the concentration of urea isaccompanied by an increase in the shear modulus.

In the production of the polyurethane polyureas according to theinvention, it is also possible in principle to incorporate other lateralpolar groups such as, for example --SO₃ H, --CN, --COOR, --CONH₂,--CONRH or --CONR₂ (R ═ C₁ -C₄ -alkyl) in addition to the lateralcarboxyl groups essential to the invention in order to improve theadhesion of the polyurethane polyureas to the glasses. However, sincethe adhesion of the polyurethane polyureas according to the invention tothe glasses is in itself excellent without this additional incorporationof polar lateral groups, this incorporation of additional polar groupsis not essential.

In the process according to the invention for producing laminated safetyglass, the polyurethane polyureas according to the invention are used inthe form of films ranging, for example, from about 0.1 to 5 mm inthickness. These films may be produced by conventional film extrusiontechniques or by casting solutions of the polyurethane polyureasaccording to the invention in suitable solvents, for example of the typementioned by way of example above, onto polished metal surfaces incasting machines and evaporating the solvent. In this way, thepolyurethane polyurea films according to the invention can be obtainedin the necessary layer thicknesses by repeated casting. Basically, it isalso possible directly to produce the film on a sheet of glass used forthe production of the laminated safety glasses by casting of a solutionand physically drying the coated film obtained. The films may also beobtained by extrusion techniques known per se.

In the production of the laminated safety glasses in accordance with theinvention, the polyurethane polyureas according to the invention areused as coating agents and/or as binders for sheets of glass and/orsheets of glass-like plastics.

Any type of silicate-containing glass of the type used for theproduction of safety glasses may be used in the process according to theinvention for producing laminated safety glass. Glasses obtainable bythe float process are preferably used.

In addition to the silicate-containing glasses known per se, synthetic"glasses" especially transparent polycarbonate films or sheets (cf. forexample U.S. Pat. No. 3,028,365 and U.S. Pat. No. 3,117,019) ortransparent films or sheets of polymerized methacrylic acid methylester, may also be used in the process according to the invention forthe production of laminated safety glass. Sheets or films of celluloseesters are also suitable. The thickness of the sheets of glass used inthe process according to the invention for producing the laminatedsafety glass is not a critical parameter and is generally between about0.1 and 10 mm. However, it is also possible to use glass films with athickness of only 100 μm or sheets of glass with a thickness of 20 mm.

The bond between the sheet of glass and the polyurethane polyureaaccording to the invention in the production of coated glasses or thebond between two or more sheets of glass using the polyurethanepolyureas according to the invention as binder, is established inprinciple by melting the film of the polyurethane polyureas according tothe invention, which generally have a melting point between about 60°and 180° C., after it has been applied to the surface of the sheet ofglass to be coated or inserted between two sheets of glass. Theproduction of composite glass by bonding several sheets of glasstogether with the polyurethane polyureas according to the invention isgenerally carried out at temperatures of from about 100° to 200° C. andunder pressures of from about 5 to 20 bars.

The following advantages are afforded by the invention:

1. Glass-clear, highly transparent polyurethane polyurea films areproduced by a process which is simple and economic in practice havingthe particular advantage over conventional films that they adherestrongly, for example to glass, and are therefore particularly suitablefor the production of laminated safety glass.

2. Composite glass panels containing the interlayer films according tothe invention are particularly superior in regard to their behaviorunder impact both at elevated temperatures and at low temperatures suchas are frequently encountered in panels exposed to weathering.

Thus, panels produced in accordance with Example 3 using films accordingto Example 2.1 of a polyurethane polyurea according to Example 1 remainintact in the dropped ball test according to DIN 52306 when the ball isdropped from a height of 5 meters at +35° C. and from a height of 5.50meters at a temperature of -20° C. This substantially corresponds to theperformance of a panel containing a standard polyvinyl butyralinterlayer at room temperature. In the above-mentioned test, the maximumdropping height withstood by the last of the above-mentioned panels at+35° C. is approximately 4m. At -8° C., the dropping height withstood bythese panels is only 2.50 meters. At -20° C., their impact strengthwould appear to be considerably lower.

The superiority of the film according to the invention is also apparentat room temperature. Dropping heights of 8 meters are still withstood bycomparison with the maximum dropping height of 6 meters withstood bypanels containing A PVB interlayer. However, the considerably betterbehavior at elevated temperatures and low temperatures is particularlyvaluable.

3. The polyurethane polyurea films according to the invention are freefrom discoloration, hazing or local swelling (cf. Examples 1, 5, 6, 9,10, 11, 12) and do not undergo any changes on exposure to sunlight.

4. In contrast for example to the polyvinyl butyral films currently inuse, the films according to the invention can be processed intocomposite glass in nonconditioned atmospheres (cf. Example 3). Inconventional polyvinyl butyral films, the need to condition the filmsarises out of the dependence of their properties upon water content (cf.G. Rodloff, Neuere Untersuchungen an Verbund-Sicherheitsglas furWindschutzscheiben (Recent Investigations Into Composite Safety Glassfor Windscreens), Automobiltechnische Zeitschrift 64, No. 6, 1962).

5. The safety glasses produced from the films according to the inventionshow excellent edge stability (cf. Example 3).

The invention is illustrated by the following Examples in which all thepercentages quoted are percent by weight.

EXAMPLES EXAMPLE 1 Production of a polyurethane polyurea in the melt

(A) In a stirrer-equipped vessel, 70 kg (31.2 mol) of a linear1,4-butane diol polyadipate containing terminal hydroxyl groups andhaving an average molecular weight of approximately 2200 and 34.7 kg(156.3 mols) of 1-isocyanato-3-isocyanatomethyl-3,3,5-trimethylcyclohexane (isophorone diisocyanate) are stirred overnight undernitrogen at a temperature of 60° C. Thereafter 7.5 kg (83.3 mols) of1,4-butane diol and 1.4 kg (10.45 mols) of dimethylol propionic acid areadded, followed by stirring for another 2 hours at 100° C. Thereafter acontent of free isocyanate groups of 2.2% is found.

(B) 600 g (0.313 mol) per second of the isocyanate-prepolymer obtainedin accordance with Example 1A and 26.6 g (0.313 mol) per second ofisophorone diamine are continuously introduced through separate pipesinto the feed hopper of a standard, heated twin-screw reaction extruder.The screws are fitted with feed and kneading elements. The length todiameter ratio of the screws amounts to about 40.

At a rotational speed of 200 min⁻¹, melt temperatures in the range from120° to 200° C. are measured over the length of the machine. The productmelt is quenched in a water bath, subsequently free from the wateradhering to it with compressed air and granulated. The reaction productis obtained in the form of a colorless glass-clear resin.

--NH--CO--NH-- content: 2.46% by weight

--COOH-- content: 0.4% by weight

shear modulus G'

at 20° C.: 56 N/mm²

at 60° C.: 1.7 N/mm²

(as determined by the oscillating torsion test according to DIN 53445).

Production of composite glass panels with the polyurethane polyureasaccording to the invention as interlayer.

EXAMPLE 2

Film production:

2.1 Extrusion:

The polyurethane polyureas produced in accordance with Example 1 in atwin-screw reaction extruder are obtained in the form of a cylindricalgranulate and can be extruded, for example through a flat-sheeting die,to form glass-clear films at a melt temperature of from 170° to 220° C.

2.2 casting from solution:

The polyurethane polyureas according to the invention, in the form ofsolutions with a solids content of approximately 20%, are cast bysuitable techniques (doctor, curtain), for example onto sheets of glassor onto a moving steel belt, and the solvent is removed either at roomtemperature or at elevated temperatures in a drying tunnel. In order toobtain bubble-free films in the required layer thicknesses of from 0.7to 0.8 mm, it is of advantage to produce the films by repeatedly castingthin layers and evaporating off the solvent before the next casting.

Producing the films by casting is particularly appropriate for producingtest specimens for determining the characteristics of the material.Extrusion would appear to be preferable for manufacturing the films on acommercial scale because it is the more economical method.

EXAMPLE 3 Production of the composite glass panels:

The polyurethane polyureas according to the invention, in the form offilms from 0.6 to 0.8 mm thick, are inserted between two sheets of glass(silicate glass) measuring, for example, 30 × 30 cm, and introduced intoa suitable autoclave. The autoclave is initially evacuated in order toremove the air between the glass and film. A preliminary bond isestablished by heating in vacuo to 80°-100° C., followed by venting. Thetemperature in the autoclave is then increased to 100°-190° C.,preferably to 120°-170° C., depending upon the polyurethane-polyureaused, and the final bond established by pressing for 5 to 30 minutes,preferably for 10 to 20 minutes, under a nitrogen pressure of from 4 to16 bars, preferably from 8 to 12 bars.

Composite glass panels produced in this way withstand the boiling testaccording to DIN 52308. Bubble formation in the peripheral zone isminimal.

EXAMPLE 4 Testing the bond strength of composite glass panels:

15 × 15 mm² samples are taken from the composite glass panels to betested. The samples, whose surfaces were roughened, were bonded betweentwo metal stamps with the same surface area (15 × 15 mm²). A standardepoxide resin adhesive was used as the adhesive(Permabond-Contact-Cement No. 747, a product of Lubben and Co., Munich).

In a tensile tester, one of the stamps was suspended in the deviceconnected to the dynamometer, while the other stamp was suspended in theseparating device. The separation rate (V) amounted to 1 mm/minute. Arecorder recorded the adhesion forces occurring during the tests. Theadhesion forces were converted to a sample cross-section of 1 mm².

Bond strength determined by this method:

Example 5: 11.0 (N/mm²)

Example 6: 11.6 (N/mm²) for comparison

Example 7: 2.5 (N/mm²)

Example 8: 3.5 (N/mm²)

EXAMPLE 5

153 g (0.09 mol) of a polyester having a hydroxyl number of 65.9synthesized from adipic acid, 1,6-hexane diol and neopentyl glycol, aredehydrated for 30 minutes at 120° C. in a water jet vacuum. Thereafter1.34 g (0.01 mol) of dimethylol propionic acid are added to the melt,followed after thorough mixing by the addition of 66.6 g (0.3 mol) ofisophorone diisocyanate (hereinafter referred to as IPDI). The whole wasthen stirred under nitrogen for 3 hours at 90° C. The isocyanate contentof the prepolymer is then determined:

isocyanate observed: 7.84%, isocyanate calculated: 7.61%.

600 g of methylene chloride are then added to the prepolymer. Themixture is then left to cool to room temperature while stirring in anitrogen atmosphere, followed by the dropwise addition over a period of30 minutes of a solution of 34 g (0.2 mol) of isophorone diamine(hereinafter referred to as IPDA) in 320 parts of methylene chloride and80 parts of methanol. A clear, colorless film solution with a viscosity(η) of 26,800 mPas. is obtained. --NH--CO--NH-- content of the solid:9.1%, --COOH-- content: 0.176%, shear modulus G' 106.0 N/mm² at 20° C.,34.9 N/mm² at 60° C.

EXAMPLE 6

180 g (0.09 mol) of a polyester having a hydroxyl number of 56 producedfrom adipic acid and ethylene glycol are mixed with 1.34 g (0.01 mol) ofdimethylol propionic acid and dehydrated for 30 minutes at 120° C. in awater jet vacuum. Thereafter 66.6 g (0.3 mol) of IPDI are added all atonce. The mixture is stirred under nitrogen for 30 minutes at 120° C.The isocyanate content of the prepolymer is then determined: isocyanateobserved: 6.65%, isocyanate calculated: 6.78%.

600 g of toluene are then added to the prepolymer. The mixture is leftto cool to room temperature while stirring in a nitrogen atmosphere,followed by the dropwise addition over a period of 30 minutes of asolution of 34 g (0.2 mol) of IPDA in 370 g of toluene and 410 g ofisopropanol. Before the last 50 ml of this solution are added, a sample(IR-spectrum) is taken from the mixture. If only very little isocyanatecan be detected by IR-spectroscopy, the chain-extending reaction isterminated. The residual chain extending agent is discarded.

--NH--CO--NH-- content of the solid: 8.23%,

--COOH-- content: 0.159%,

shear modulus G'

62.0 n/mm² at 20° C.,

32.0 n/mm² at 60° C.

COMPARISON EXAMPLE 7 (without dimethylol propionic acid)

200 g (0.1 mol) of the polyester of Example 6 are dehydrated for 30minutes at 120° C. in a water jet vacuum. 44.4 g (0.2 mol) of IPDI arethen added all at once. The mixture is stirred under nitrogen for 30minutes at 120° C. Thereafter the isocyanate-content of the prepolymeris determined. Isocyanate observed: 3.28%, isocyanate calculated: 3.44%.

600 g of toluene are then added to the prepolymer. The mixture is thenleft to cool to room temperature while stirring in a nitrogenatmosphere, followed by the dropwise addition over a period of 30minutes of a solution of 17 g (0.1 mol) of IPDA in 370 g of toluene and410 g of isopropanol. Before the last 50 ml of this solution are added,a sample (IR-spectrum) is taken from the mixture. If only very littleisocyanate can be detected by IR-spectroscopy, the chain-extendingreaction is terminated. The residual chain-extending agent is discarded.

--NH--CO--NH-- content of the solid: 4.44%

--COOH-- content: 0%

shear modulus G'

5.5 n/mm² at 20° C.

2.0 n/mm² at 60° C.

COMPARISON EXAMPLE 8 (without dimethylol propionic acid)

170 g (0.1 mol) of the polyester of Example 5 are dehydrated for 30minutes at 120° C. in a water jet vacuum. 44.4 g (0.2 mol) of IPDI arethen added all at once. The mixture is stirred under nitrogen for 30minutes at 120° C. The isocyanate-content of the prepolymer is thendetermined. Isocyanate observed: 3.98%, isocyanate calculated: 3.93%.

600 g of toluene are then added to the prepolymer. The mixture is leftto cool to room temperature while stirring in a nitrogen atmosphere,followed by the dropwise addition over a period of 30 minutes of asolution of 17 g (0.1 mol) of IPDA in 210 g of toluene and 340 g ofisopropanol. Before the last 50 ml of this solution are added, a sample(IR-spectrum) is taken from the mixture. If only very little isocyanatecan be determined by IR-spectroscopy, the chain-extending reaction isterminated. The residual chain-extending agent is discarded.

--NH--CO--NH-- content of the solid: 5.01%

--COOH-- content: 0%

shear modulus G'

7.6 n/mm² at 20° C.

2.7 n/mm² at 60° C.

From the polyurethane polyurea solutions (according to Examples 7 and8), films are produced by casting in accordance with 2.2 and compositeglass panels are produced in accordance with 3. Composite glass panelsproduced in this way show poor adhesion to glass (cf. adhesion test,Example 4).

EXAMPLE 9

336 g (0.15 mol) of a polyester (having a hydroxyl number of 50 producedfrom adipic acid and 1,4-butane diol are dehydrated for 30 minutes at120° C./15 Torr. 36 g (0.4 mol) of 1,4-butane diol and 6.7 g (0.05 mol)of dimethyl propionic acid are introduced into the melt, followed afterthorough mixing by the addition of 166.5 g (0.75 mol) of IPDI. The meltis stirred under nitrogen for 40 minutes at 120° C. The isocyanatecontent of the prepolymer is then determined.

Isocyanate observed: 2.1%, isocyanate calculated: 2.3%.

300 g of toluene are then added to the prepolymer. The mixture is thenleft to cool to room temperature while stirring in a nitrogenatmosphere, followed by the dropwise addition over a period of 30minutes of a solution of 25.2 g (0.12 mol) of 4,4'-diaminodicyclohexylmethane in 891 g of toluene and 510 g of isopropanol. Thereafter onlyvery little isocyanate can be detected by IR-spectroscopy.

--NH--CO--NH-- content of the solid: 2.44%

--COOH-- content: 0.39%

shear modulus G'

38.0 n/mm² at 20° C.

1.6 n/mm² at 60° C.

EXAMPLE 10

336 g (0.15 mol) of a polyester (having a hydroxyl number of 50 producedfrom adipic acid and butane diol are dehydrated for 30 minutes at 120°C./15 Torr. 40.5 g (0.45 mol) of 1,4-butane diol, 0.134 g (0.001 mol) ofdimethylol propionic acid and 166.4 g (0.75 mol) of IPDI are then addedto the melt. The mixture is stirred under nitrogen for 90 minutes at120° C. The isocyanate-content of the prepolymer is then determined.Isocyanate observed: 2.12%, isocyanate calculated: 2.32%. 300 g oftoluene are then added to the prepolymer. The mixture is left to cool toroom temperature, followed by the dropwise addition over a period of 30minutes of a solution of 20.4 g (0.12 mol) of IPDA in 891 g of tolueneand 510 g of isopropanol. On completion of the addition, only verylittle isocyanate can be detected by IR-spectroscopy.

--NH--CO--NH-- content of the solid: 2.47%

--COOH-- content: 0.008%

shear modulus G'

42.0 n/mm² at 20° C.

1.8 n/mm² at 60° C.

EXAMPLE 11

1900 g (0.95 mol) of a propylene glycol-started polyether, in whichpropylene oxide has been polyadded in the presence of sodium alcoholateup to a hydroxyl number of 56 (functionality 2), and 6.7 g (0.05 mol) ofdimethylol propionic acid are mixed and dehydrated for 30 minutes at100° C./20 Torr. 0.5 g of dibutyl tin dilaurate (as catalyst) and 666 g(3 mols) of IPDI are added to the mixture, followed by stirring undernitrogen for 30 minutes at 100° C. Thereafter the isocyanate-contentamounts to 6.4% (isocyanate calculated: 6.53%). 6100 g of toluene areadded to the melt and the mixture is left to cool to room temperature. Asolution of 332.5 g (1.96 mol) of IPDA in 2620 g of isopropanol is thenadded dropwise to the mixture over a period of 30 minutes. A clearlow-viscosity solution is obtained.

--NH--CO--NH-- content of the solids: 7.82%

--COOH-- content: 0.077%

shear modulus G'

7.5 n/mm² at 20° C.

4.6 n/mm² at 60° C.

EXAMPLE 12

200 g (0.1 mol) of a polyester having a hydroxyl number of 56 of adipicacid and ethylene glycol are mixed with 55.26 g (0.09 mol) of apropylene glycol-started polyether having a hydroxyl number of 183, inwhich first propylene oxide and then ethylene oxide have been polyaddedin the presence of sodium methylate, and with 1.34 g (0.01 mol) ofdimethylol propionic acid, followed by dehydration for 30 minutes at120° C./15 Torr. 88.8 g (0.4 mol) of IPDI are then added to the mixtureall at once, after which the mixture is stirred under nitrogen for 2hours. The isocyanate-content then amounts to 4.85% (isocyanatecalculated: 4.9). 700 g of toluene are then introduced into the meltwhich is then left to cool to room temperature, followed by the dropwiseaddition of 34 g (0.2 mol) of IPDA dissolved in 97 g of toluene and 342g of isopropanol. A clear highly viscous solution is obtained.

--NH--CO--NH-- content of the solid: 6.11%

--COOH-- content: 0.118%

shear modulus G'

55.0 n/mm² at 20° C.

9.8 n/mm² at 60° C.

EXAMPLE 13

Two 30 × 30 cm polycarbonate panels with a thickness of 4 mm and a 0.8mm thick film of the polyurethane polyurea of Example 1 (PUR) arepreheated for 30 minutes to 80°-90° C. The film is then placed betweenthe two polycarbonate panels and the system exposed for a few minutes toa pressure of around 40 bars (for example in a multidaylight press) inorder to remove as much as possible of the air between the panels andfilm. A pre-laminate is formed and may be handled without the individuallayers becoming separated from one another. The prelaminate is thenintroduced into an autoclave which is heated to 140° C. The autoclave isleft at this temperature for 30 minutes under a nitrogen pressure of 15bars and then cooled under pressure. (This procedure substantiallycorresponds to the conditions normally applied in the production ofconventional composite glass). It is best to keep the laminate betweensupporting panels of glass or metal during its production in order toprevent possible deformation of the polycarbonate panels at theprocessing temperature. An extremely tough glass-clear laminate isobtained. The adhesion between polycarbonate and polymethane isextremely strong. It may be additionally varied by suitably selectingthe lamination temperature.

EXAMPLE 14

The procedure is as in Example 13, except that a multilayer laminate ofthree 4 mm thick polycarbonate panels is built up by the processdescribed in that Example, a 2.5 mm thick layer of a polyurethanepolyurea according to the invention being inserted between twopolycarbonate panels. A transparent laminate is again obtained. Thislaminate is bullet proof under fire with 6 mm ammunition.

EXAMPLE 15 Polycarbonate-PUR-glass composite

A 0.8 mm thick film of the polyurethane polyurea of Example 1 accordingto the invention is placed on a 30 × 30 cm large 2.8 mm thick plate ofglass, followed by the application of a 3 mm thick polycarbonate plate.The procedure is then as in Example 3, the prelaminate being produced byheating in vacuo at 80° C. The prelaminate is then kept under a pressureof 15 bars for 30 minutes at a temperature of 140° C. It is then cooledunder pressure. A glass clear laminate free from air bubbles isobtained. Although the glass breaks under impact (for example with ahammer or thrown stone), it does not become separated from thepolycarbonate. Laminates of polycarbonate and glass produced with thepolyurethane polyureas according to the invention are extremely stableto light. They do not yellow, even after prolonged exposure to sunlight.

EXAMPLE 16

The procedure is as in Example 15, except that a 200 μm thick glass filmis used instead of a glass plate. In another variant of this Example, astructure of glass film/PUR film/polycarbonate panel/PUR film is used,again with glass film as the outer layer. The laminates formed arecharacterized by extreme toughness of the polycarbonate and PUR layerand by the surface quality (hardness, scratch resistance) of the glass.

EXAMPLE 17

Following the procedure of Example 13, a composite structure of two 4 mmthick panels of polymethyl methacrylate (PMMA) (for example Plexiglas®)with a 0.8 mm thick polyurethane interlayer is produced in an autoclaveat 130° C./15 bars. The glass clear laminate is tougher than a compactPMMA panel of comparable thickness.

EXAMPLE 18

5 layers of a 0.8 mm thick film of the polyurethane polyurea of Example1 are placed on a 50 × 20 cm large, 10 mm thick plate of glass, followedby the application of a 3 mm thick plate of glass. This assemblage isheated to 80°-90° C. and then passed through squeezing rollers forventing. The final laminate is then produced in the usual way, i.e. inan autoclave over a period of 30 to 45 minutes at 140°-145° C./15 bars.The transparent laminate thus produced withstands fire from a 0.4 mmmagnum revolver at a range of 4 meters.

EXAMPLE 19

The procedure is as in Example 3, except that a plate of glass coatedbeforehand with release agent, for example a standard commercial-gradepolysiloxane or fluorine polymer, is used for covering the PUR film onone side. After the laminate has been produced, this plate of glass canbe lifted off. A two-layer laminate of glass and the film according tothe invention is obtained. The advantage of laminates such as these isthat, when the laminate is subjected to impact on the film side,virtually no injuries can be caused through cuts. The energy-absorbingcapacity is not impaired by comparison with the laminates of Example 3.

Although the invention has been described in detail for the purpose ofillustration, it is to be understood that such detail is solely for thatpurpose and that variations can be made therein by those skilled in theart without departing from the spirit and scope of the invention exceptas it may be limited by the claims.

What is claimed is
 1. Polyurethane polyureas with a predominantly linearmolecular structure exclusively containing aliphatically orcycloaliphatically bound urethane and urea segments and having a shearmodulus G' (DIN 53 445) which amounts to between 2 and 140 N/mm² at 20°C. and does not fall below a value of 1 N/mm² at 60° C., characterizedby(a) a content of urea groups --NH--CO--NH-- amounting to between 1 and20% by weight and (b) a content of lateral carboxyl groups --COOHdirectly attached to the main chain of the molecule amounting to between0.001 and 10% by weight.
 2. A process for the production of thepolyurethane polyureas claimed in claim 1 by reacting excess quantitiesof organic diisocyanates with aliphatically and/or cycloaliphaticallybound isocyanate groups with dihydroxy polyesters and/or dihydroxypolyethers having a molecular weight in the range from 300 to 6000,aliphatic dihydroxy monocarboxylic acids and, optionally, aliphatic orcycloaliphatic dihydric alcohols with a molecular weight in the rangefrom 62 to 300, to form the corresponding NCO-prepolymers containing twoterminal isocyanate groups, followed by reaction of theseNCO-prepolymers with organic diamines containing aliphatically and/orcycloaliphatically bound primary amino groups and having a molecularweight in the range from 60 to 300, monofunctional synthesis componentsoptionally being used in small quantities for adjusting the particularmolecular weight required, wherein(a) the dihydroxy carboxylic acid usedcorresponds to the formula ##STR3## in which R represents hydrogen or analkyl radical with 1 to 4 carbon atoms, the quantity in which thisdihydroxy carboxylic acid is used being such that the polyurethanepolyurea obtained contains from 0.001 to 10% by weight of lateralcarboxyl groups, and (b) the quantitative ratio between diisocyanates,dihydroxyl compounds and diamines is selected in such a way that thepolyurethane polyurea contains from 1 to 20% by weight of urea groups--NH--CO--NH.
 3. A polyurethane polyurea comprising the reaction productof(a) dihydroxy compounds having molecular weights between about 300 and6,000 selected from the group consisting of polyesters and polyethers,(b) dihydroxy carboxylic acids corresponding to the formula ##STR4##wherein R represents H, or a C₁ to C₄ alkyl radical, (c) optionallyaliphatic or cycloaliphatic diols having molecular weights of betweenabout 62 and 300, (d) diisocyanates having exclusively aliphatically andcycloaliphatically bound isocyanate groups, and (e) organic diaminescontaining aliphatically and cycloaliphatically bound primary aminogroups and having molecular weights between about 60 and 3,000, whereinthe equivalent ratio of d:(a+b+c) is between about 1.1:1 and 4:1, theequivalent ratio of e:(a+b+c) is between about 0.1:1 and 3:1, the molarratio of a:b is between about 1:0.01 and 1:12, and the molar ratio ofa:c is between about 1:0 and 1:10, said polyurethane polyurea having(1)a molecular weight greater than about 10,000, (2) a urea group contentof between about 1 and 20 wt. %, and (3) a content of lateral carboxylgroups directly attached to the main chain of the molecule of betweenabout 0.001 and 10 wt. %.
 4. The polyurethane polyurea of claim 3wherein(a) component a) comprises compounds having molecular weight ofbetween about 800 and 3,000, (b) the diisocyanates are of the formulaQ(NCO)₂ wherein Q represents an aliphatic hydrocarbon radical of 2 to 12carbon atoms or a cycloaliphatic hydrocarbon radical of 4 to 15 carbonatoms, (c) the ratio of d:(a+b+c) is between about 1.2:1 and 3:1 and theratio of e:(a+b+c) is between about 0.2:1 and 2:1, (d) said polyurethanepolyurea has(1) a molecular weight between about 20,000 and 200,000, (2)a urea group content of between about 2 and 10 wt. %, and (3) a contentof carboxyl groups directly attached to the main chain of the moleculeof between about 0.008 and 6 wt. %.
 5. A polyurethane polyureacomprising the reaction product of(a) a dihydroxy polyester or polyetherhaving a molecular weight of between about 800 and 3,000, (b)α,α-dimethylol propionic acid, (c) optionally aliphatic orcycloaliphatic diols having molecular weights of between about 62 and300, (d) 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane,and (e) diamines selected from 4,4'-diamino dicyclohexyl methane and1-amino-3,3,5-trimethyl-5-amino methyl cyclohexane, wherein the NCO toOH ratio is between 1.2:1 and 3:1 and the amino to OH ratio is between0.2:1 and 2:1, said polyurethane polyurea having(1) a molecular weightbetween about 20,000 and 200,000, (2) a urea group content of between 2and 10 wt. %, and (3) a content of carboxyl groups directly attached tothe main chain of the molecule of between about 0.008 and 6 wt. %.
 6. Atransparent film 0.1 to 5 mm in thickness formed from the polyurethanepolyurea of claim
 3. 7. A process for the production of transparentpolyurethane polyureas comprising(a) reacting at between about 80° and150° C.(1) dihydroxy polyesters or polyethers having molecular weightsof between about 300 and 6,000, (2) dihydroxy carboxylic acids of theformula ##STR5## wherein R represents H or C₁₋₄ alkyl, and (3)optionally aliphatic or cycloaliphatic diols having molecular weights ofbetween about 62 and 300, with (4) diisocyanates having exclusivelyaliphatically and cycloaliphaticaly bound isocyanate groups at an NCO toOH ratio of between about 1.1:1 and 4:1, and (b) chain extending theprepolymer produced by extrusion at between about 120° and 300° C. withorganic diamines containing aliphatically and cycloaliphatically boundprimary amino groups and having molecular weights between about 60 and3000.